Microresonator Concept for Mass Detection in Liquids

We evaluate enhanced mass detection possibilities with electrostatic actuation of a mechanical microoscillator positioned at a fluid-liquid interface. An analytical model is used to simulate the rotational motion of such configuration inside a microchannel either completely filled with two immiscible liquids, or partially filled forming an air-liquid interface. Simulation results show that improvements in sensitivity can be obtained through the use of fluid-liquid interfaces. For point mass detection, sensitivities of at least 9–15Hz/ng can be achieved using liquid-liquid interfaces. For air-liquid interfaces, it is conceivable to detect point masses in the order of tens of picograms.